Inner ear test battery aligned with Hydrops MRI to differentiate acute-onset sensorineural hearing loss

INTRODUCTION: This study differentiates cases of acute-onset sensorineural hearing loss (SNHL) that did not meet the diagnostic criteria for either sudden SNHL or Meniere's disease, leading to a diagnostic challenge. METHODS: All 46 patients with acute-onset SNHL underwent an inner ear test battery followed by Hydrops MRI. Twenty-four patients (28 ears) who tested positive for endolymphatic hydrops (EH) on Hydrops MRI were referred to EH group. Another 22 patients (22 ears) who tested negative for EH were classified as non-EH group. RESULTS: Significant difference in the mean hearing levels between EH and non-EH groups was identified at frequencies of 125, 250, 500 and 1000 Hz, but not at frequencies ranging from 2000 Hz through 8000Hz. A declining sequence of abnormality rates-from audiometry (96%), cervical vestibular-evoked myogenic potential (cVEMP) test (75%), ocular VEMP test (57%) to the caloric test (43%)-was observed in the EH group, but not in the non-EH group. This pattern closely paralleled the decreasing prevalence of EH on Hydrops MRI, which moved from the cochlea (79%), saccule (61%), utricle (57%) to the semicircular canals (4%). CONCLUSION: A comprehensive inner ear test battery aligned with Hydrops MRI may enhance understanding of disease mechanisms, and aid differential diagnosis in selected ambiguous cases of acute-onset SNHL, whether or not it arises from EH.